7660777731721 has 27 divisors (see below), whose sum is σ = 7839321057589. Its totient is φ = 7486286622848.

The previous prime is 7660777731671. The next prime is 7660777731779. The reversal of 7660777731721 is 1271377770667.

The square root of 7660777731721 is 2767811.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in 4 ways, for example, as 446912305225 + 7213865426496 = 668515^2 + 2685864^2 .

It is a de Polignac number, because none of the positive numbers 2^k-7660777731721 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 7660777731721.

It is not an unprimeable number, because it can be changed into a prime (7660777731521) by changing a digit.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 33747919410 + ... + 33747919636.

Almost surely, 2^{7660777731721} is an apocalyptic number.

7660777731721 is the 2767811-st square number.

7660777731721 is the 1383906-th centered octagonal number.

It is an amenable number.

7660777731721 is a deficient number, since it is larger than the sum of its proper divisors (178543325868).

7660777731721 is an frugal number, since it uses more digits than its factorization.

7660777731721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 906 (or 453 counting only the distinct ones).

The product of its (nonzero) digits is 25412184, while the sum is 61.

The spelling of 7660777731721 in words is "seven trillion, six hundred sixty billion, seven hundred seventy-seven million, seven hundred thirty-one thousand, seven hundred twenty-one".